function base64_encode(str) {
  var c1, c2, c3;
  var base64EncodeChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
  var i = 0,
      len = str.length,
      string = '';

  while (i < len) {
    c1 = str.charCodeAt(i++) & 0xff;

    if (i == len) {
      string += base64EncodeChars.charAt(c1 >> 2);
      string += base64EncodeChars.charAt((c1 & 0x3) << 4);
      string += "==";
      break;
    }

    c2 = str.charCodeAt(i++);

    if (i == len) {
      string += base64EncodeChars.charAt(c1 >> 2);
      string += base64EncodeChars.charAt((c1 & 0x3) << 4 | (c2 & 0xF0) >> 4);
      string += base64EncodeChars.charAt((c2 & 0xF) << 2);
      string += "=";
      break;
    }

    c3 = str.charCodeAt(i++);
    string += base64EncodeChars.charAt(c1 >> 2);
    string += base64EncodeChars.charAt((c1 & 0x3) << 4 | (c2 & 0xF0) >> 4);
    string += base64EncodeChars.charAt((c2 & 0xF) << 2 | (c3 & 0xC0) >> 6);
    string += base64EncodeChars.charAt(c3 & 0x3F);
  }

  return string;
}

function base64_decode(str) {
  var c1, c2, c3, c4;
  var base64DecodeChars = new Array(-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1, -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1);
  var i = 0,
      len = str.length,
      string = '';

  while (i < len) {
    do {
      c1 = base64DecodeChars[str.charCodeAt(i++) & 0xff];
    } while (i < len && c1 == -1);

    if (c1 == -1) break;

    do {
      c2 = base64DecodeChars[str.charCodeAt(i++) & 0xff];
    } while (i < len && c2 == -1);

    if (c2 == -1) break;
    string += String.fromCharCode(c1 << 2 | (c2 & 0x30) >> 4);

    do {
      c3 = str.charCodeAt(i++) & 0xff;
      if (c3 == 61) return string;
      c3 = base64DecodeChars[c3];
    } while (i < len && c3 == -1);

    if (c3 == -1) break;
    string += String.fromCharCode((c2 & 0XF) << 4 | (c3 & 0x3C) >> 2);

    do {
      c4 = str.charCodeAt(i++) & 0xff;
      if (c4 == 61) return string;
      c4 = base64DecodeChars[c4];
    } while (i < len && c4 == -1);

    if (c4 == -1) break;
    string += String.fromCharCode((c3 & 0x03) << 6 | c4);
  }

  return string;
}

module.exports = {
  'base64_encode': base64_encode,
  'base64_decode': base64_decode
};